The present invention relates to oral hygiene and specifically to the frequent interference with the formation of plaque and/or the control of gingivitis, hypersensitivity, etc., by regularly chewing a specially coated chewing gum. Plaque is a microbial coating on tooth surfaces, bound together by natural polymers, (mucopolysaccharides,) formed by microbial action on the cell debris, food remnants, sugars and starches in the mouth. Embedded in this polymer matrix are the bacteria normal to the oral cavity but, when trapped against tooth surfaces and protected by the matrix from easy removal, are in excellent position for "mischief." Most dental texts implicate plaque in the formation of caries, or tooth decay. In addition, these embedded bacteria release toxins that cause gingivitis, bleeding and swelling of the gums. Gingivitis can lead to periodontitis in which gums recede, pockets of infection form and teeth loosen.
Plaque formation is an ongoing process. Various gel and paste dentifrice preparations, mouth rinses, mouth prerinses and spray preparations make plaque and/or tartar control claims. One disadvantage of these toothpaste and rinse preparations is that only a relatively short time during which the teeth are being cleaned or the mouth is being rinsed is available for these preparations to take effect. These preparations generally have little residual effect on plaque formation. Additionally, some of these preparations such as mouth rinses and prerinses contain various antimicrobial substances which may alter the critically balanced microflora of the mouth. Another disadvantage of these toothpaste and rinse preparations is the general infrequency of use. That is, most are used once or perhaps twice daily and seldom when they are most needed, e.g., after meals, snacks, smoking, drinking, coffee breaks, etc. The present invention also relates to therapeutic oral hygiene preparations including preparations suitable for the control of gingivitis.
Effective oral hygiene requires that three control elements be maintained by the individual:
1. Physical removal of stains, plaque and tartar. This is accomplished in the strongest sense by scraping and abrasion in the dentist's office. Self administered procedures are required frequently between visits and range from tooth brushing with an appropriate abrasive toothpaste through flossing and water jet action down to certain abrasive foods and even the action of the tongue against tooth surfaces. PA1 2. Suffactant Cleansing. This is required to remove food debris and staining substances before they adhere to the tooth surfaces as well as normal dead cellular (epithelial) material which is continually sloughed off from the surfaces of the oral cavity and microbial degradation products derived from all of PA1 3. Frequency of Cleansing. This is perhaps the most difficult to provide in today's fast-paced work and social environment. Most people recognize that their teeth should be brushed at least 3 times a day plus after each snacking occasion. PA1 dilute and clear food debris and fermentable carbohydrates from the mouth, PA1 deliver buffers such as bicarbonate, proteins, urea, to the plaque, PA1 neutralize plaque acid due to buffering action and dilution, PA1 inhibit mineral loss due to shorter time of acid exposure, and PA1 promote enamel, remineralization due to higher pH and the enamel protective effects of calcium, phosphate and fluoride. PA1 A. Some prior art methods have been disclosed for the incorporation of active or insoluble ingredients into sugar containing gum bases, U.S. Pat. No. 3,075,884 teaches a method for obtaining the release of solid active ingredients from a gum base by dispersing the solid active ingredient throughout the corn syrup ingredient of the gum prior to the admixture of the corn syrup with the gum base; U.S. Pat. No. 3,011,919 teaches a method for incorporating active ingredients, including phosphates, into slab chewing gum, by coating the active ingredients with wet sugar; PA1 B. U.S. Pat. No. 3,352,689 does disclose the formulation of a sugarless gum prepared from gum base, gum acacia-in-water, gum acacia powder, sorbitol, mannitol, sweeteners and flavoring agents, which may contain additional active ingredients such as phosphates; however, no statement is made concerning the form in which these active ingredients must be or the manner for incorporating these active ingredients into the sugarless gum formulation so as to insure the release of effective amounts of the active ingredients into the oral cavity. See also U.S. Pat. No. 3,655,866; PA1 C. It is also well known in the art that mineral adjuvants such as calcium carbonate are added to chewing gum compositions to act as fillers or to provide non-stick properties. Thus, for example, U.S. Pat. No. 4,357,355, to E. Koch et al., discloses a non-stick bubble gum base composition that contains about 5% to about 25% by weight of calcium carbonate; PA1 D. A number of chewing gum compositions have been disclosed in the art which are said to inhibit or reduce plaque in the oral cavity. For example, U.S. Pat. Nos. 4,148,872, 4,150,112, 4,156,715, 4,156,716, 4,157,385, 4,159,315, 4,160,054, 4,160,820, 4,161,517, and 4,170,632, all to A. Wagenknecht et al., disclose chewing gum compositions effective in inhibiting or reducing plaque in the oral cavity. These chewing gum compositions contain a chewing gum base and a surface active agent, and, in some instances, a zinc compound or a plaque inhibiting flavor. In addition, a calcium carbonate abrasive may be included in the aforementioned chewing gum compositions. See also, U.S. Pat. Nos. 3,974,293, 3,984,574; 3,651,206; 4,568,537; 4,474,749 and 4,828,820. U.S. Pat. No. 4,029,760 discloses pharmaceutical chewing gums for the treatment of gingivitis containing at least one carrageenin; PA1 E. U.S. Pat. No. 4,400,372, to J. C. Muller et al., discloses a chewing gum composition containing a chewing gum base, at least one non-toxic source of an acid and calcined kaolin particles having a median diameter of 2 micrometers of less, wherein substantially all of the kaolin particles are less than 20 micrometers in diameter; PA1 F. U.S. Pat. No. 3,590,120, to J. C. Muller, discloses a chewing gum composition containing an insoluble gum base; zirconium silicate particles as a cleaning and polishing agent, wherein at least 20% by weight of said particles are up to about 3 microns in size and between 5% and 40% by weight are about 10 to about 20 microns in size; and a dental plaque removing agent which may be sodium carbonate, sodium bicarbonate, or chloroform. See also U.S. Pat. Nos. 3,255,018 and 3,651,206; and PA1 G. The use of cationic antimicrobial agents to reduce plaque and gingivitis has been recognized for many years wherein these antimicrobial compositions are included in the chewing gum base. Included among references disclosing, such compositions are U.S. Pat. Nos. 3,937,805, Feb. 10, 1976 to Harrison; 3,937,807, Feb. 10, 1976 to Haefele; 4,080,441, Mar. 21, 1978 to Gaffar et al.; 4,241,049, Dec. 23, 1980 to Colodney et al.; 3,925,543, Dec. 9, 1975 to Donohue; 4,256,731, Mar. 17, 1981 to Curtis et al.; 4,217,342, Aug. 12, 1980 to Gaffar; 4,259,316, Mar. 31, 1981 to Nakashima et al.; 4,039,409, Jan. 4, 1982 to CollPalagos et al.; and U.S. Pat. No. 4,169,885, Oct. 2, 1979 to Raaf et al. PA1 A. Yolles, in U.S. Pat. No. 3,818,107 issued Jun. 18, 1974, describes chewing gums which incorporate the flavor in a polymeric backbone. Yolles states that the flavor release in the chewing gum is sustained by the molecular arrangement of the flavor group. In U.S. Pat. No. 3,651,206 issued to Litchfield et al., on Mar. 21, 1872, are described chewing gums containing various aliphatic aldehydes as anticaries agents. Various oral preparations for preventing dental plaque are described in U.S. Pat. No. 3,940,476 issued Feb. 24, 1976 to Hass. Comollo states in U.S. Pat. No. 3,984,574 issued Oct. 5, 1976 that non-tacky chewing gums may be made containing mono- and diglycerides of fatty acids in an amount up to ten percent (10%) by weight of the base composition; PA1 B. Clark, in U.S. Pat. No. 3,930,026 issued Dec. 30, 1975, describes the enhancement of flavor in chewing gums obtained by sorbing the flavoring onto a hydrophilic colloid in conjunction with a surfactant. Among the surfactants disclosed are anionic materials, including sodium di(2-ethylhexyl)sulfosuccinate. Clark also states that nonionic surfactants may be used to sorb the flavor into the gum including fatty acid monoglycerides or fatty acid diglycerides; PA1 British Pat. No. 1,296,952 reported by Cancro et al. and published Nov. 22, 1972 states that plaque and calculus may be diminished by zinc phenolsulphonate and certain enzymes in dentifrice compositions. The Cancro patent also describes the use of certain abrasives, buffering agents, and various surfactants. British Pat. No. 1,372,932 published Nov. 6, 1974, describes purported anticaries compositions including chewing gums, dentifrices and candy-like products. In particular, the aforementioned British patent states that stearol-2-lactylate has been found effective to inhibit the production of dextran in the mouth; PA1 C. U.S. Pat. No. 3,821,417 issued to Westall et al. on Jun. 28, 1974, describes the use of dihydrochalcone in chewing gums. This patent further describes the use of butylated hydroxyanisole, butylated hydroxytoluene and propyl gallate as antioxidants in chewing gums. Duross, in U.S. Pat. No. 3,973,041 issued Aug. 3, 1976 describes the use of sorbitol powder, butylated hydroxyanisole, and glycerine in chewing gums. Additional disclosures of sorbitol as well as other sugars,such as xylitol, are made in various United States Patents including: U.S. Pat. No. 4,000,320 issued to Klose et al., on Dec. 28, 1976; U.S. Pat. No. 3,899,593 issued to Hammond et al., on Aug. 12, 1975; U.S. Pat. No. 3,914,434 issued Oct. 21, 1975 to Bohni; U.S. Pat. No. 3,296,079 issued Jan. 3, 1967 to Griffin; and U.S. Pat. No. 3,655,866 issued Apr. 11, 1972 to Billoti; and PA1 D. Various additives for chewing gums have been suggested to reduce or eliminate the problem of chewing gum adhering to dentures and artificial teeth, such as lecithin as disclosed in U.S. Pat. No. 2,197,719, lanolin as disclosed in U.S. Pat. No. 2,197,718 and silicone oils as disclosed in U.S. Pat. No. 2,761,782. U.S. Pat. No. 3,255,018 to Comollo discloses the use of water-soluble hydrolyzable tannin, such as tannic acid or polymer-tannic acid edicts, in combination with type A or B gelatin water-containing hydrophilic polymer gels. See also U.S. Pat. Nos. 2,273,425; 2,383,145; 2,429,664; 3,285,450; 3,440,060 and 3,984,574. PA1 A. Tomlinson in U.S. Pat. No. 4,130,636 discloses dental creams and mouthwash compositions free from bitter surfactant taste wherein the surfactant is an alkyl polyglycol ether carboxylate. A mouthwash having superior taste characteristics and improved clarity is disclosed by Januszewski in U.S. Pat. No. 3,639,563. The improved clarity is obtained by selecting nonionic surface active agents for their ability to solubilize one or more oily components contained in the mouthwash. Thus, polyoxypropylene-polyoxyethylene block polymers and polyoxyethylene derivatives of sorbitan esters are disclosed as useful surfactants which solubilize certain oily components and thus provide improved clarity in the mouthwash; PA1 Pensak et al., in U.S. Pat. No. 3,947,570, also disclose a visually clear, haze-free mouthwash free from unpleasant taste which includes a nonionic surfactant which is a polyoxyethylene derivative of a sorbitan ester; PA1 B. Jackson et al., in U.S. Pat. No. 2,677,700, disclose polyoxyalkylene surface-active block polymers, Example 6 thereof disclosing a propoxylated cetyl alcohol. There is an indication, in Column 24, that the surface active agents disclosed would have freedom from the usual bitter taste generally associated with nonionic suffactants of the prior art, and PA1 C. Schmolka, U.S. Pat. No. 4,465,661 discloses various Pluronic-type, nonionic surfactants suitable for use in various oral care products. PA1 a. the addition of lanolin and lecithin to chewing gum mixes to decrease tackiness and reduce cohesive properties, U.S. Pat. Nos. 2,197,718 and 2,197,719 respectively; PA1 b. the addition of certain paraffin waxes to chewing gum mixes imparts smoothness and freedom from tack, U.S. Pat. No. 2,137,746; PA1 c. chewing gum compositions possessing anticaries activity based on the addition of various aldehydic compounds to the gum base, U.S. Pat. No. 3,651,206; PA1 d. abhesive chewing gum compositions, U.S. Pat. No. 3,984,574, and PA1 e. a method of preventing tooth remineralization, U.S. Pat. No. 4,568,537. PA1 (1) suppress the tendency of the surfactant cleaners present to foam; PA1 (2) are safely ingestible at the concentrations used; PA1 (3) have an affinity for mouth and teeth surfaces; PA1 (4) are neutral, inert and do not support biological activity; PA1 (5) modify the surface energy properties of surfaces of the mouth such that it is more difficult for food particles, cellular debris and various plaque precursors and formers to attach to these surfaces; PA1 (6) form a thin, transparent coating that does not build up on mouth surfaces and is removed by the normal clearing and flushing action of the mouth; PA1 (7) impart a pleasant "smooth" feeling to the surfaces of the mouth and teeth, and PA1 (8) are insoluble in the surfactant or emulsifiers used herein. PA1 1. restricts the subsequent adherence of plaque forming materials to the teeth, thus continuing the disruption of plaque formation; PA1 2. continues to impart a "smooth" feeling to the mouth, prolongs the flavor perception of the coated chewing gums of the present invention, and PA1 4. reduces the "fatigue" and "tired of chewing gum" factor, allowing for longer pleasure and contact time for various therapeutic substances which may be included in the coating. PA1 1. the mouth feels exceptionally clean and smooth and the surfaces of the teeth are slick and shiny. This well lubricated feeling of the mouth is particularly beneficial to mouth breathers and those afflicted with mouth dryness; PA1 2. the prolonged flavor perception is generally described as "freshness": and persists much longer with the compositions of the present invention than when the same flavor is introduced into the mouth in the form of a conventional uncoated chewing gum. This residual flavor benefit is an important element contributing to frequency of use, and PA1 3. prior to swallowing the surfactant-polydimethyl siloxane coating, saliva mixture that is released during chewing of the gum, the user perceives that the combination is "doing something" in the mouth. This perceived signal of efficacy re-enforces repeat usage and often motivates the user to a more frequent use pattern, a key element in maximizing the efficacy of the present invention. This increased frequency of use is perceived as a major advance in oral care compliance and should be welcomed by most oral care professionals. PA1 A. Water-soluble sweetener such as monosaccharides, disaccharides, and polysaccharides such as xylose, ribose, glucose, mannose, galactose, fructose, dextrose, sucrose, maltose, partially hydrolyzed starch or corn syrup solids and sugar alcohols such as sorbitol, xylitol, mannitol, hydrogenated glucose syrup and mixtures thereof, and PA1 B. Water-soluble artificial sweeteners such as the soluble saccharin salts, i.e., sodium or calcium saccharin salts, cyclamate salts, such as the sodium salt and the like, and the free acid form of saccharin; dipeptide based sweetening agents such as L-aspartyl-L-phenyl-alanine methyl ester and materials described in U.S. Pat. Nos. 3,492,131 and 3,642,491 and the like; dihydrochalcone; glycyrrhizin; Stevia rebaudiana (Stevioside); and the synthetic sweetener 3,6-dihydro-6-methyl-1,2,3-oxathiazin-4-one-2,2-dioxide, particularly the potassium (Acesulfame-K), sodium and calcium salts thereof, as described in German Pat. No. 2,001,017.7. PA1 a. be applied to conventional chewing gum in a controlled means, PA1 b. be released at a substantially constant, therapeutically effective, dosage level from the chewing gum during chewing, PA1 c. be released at a substantially constant therapeutically effective release rate from the chewing gum during chewing, PA1 d. substantially avoid being entrapped and/or bound in the chewing gum base during chewing, PA1 e. be applied to conventional chewing gum while avoiding interfering with chewing gum manufacturing processes, and PA1 f. be applied to chewing gum without negatively effecting the hedonic properties of said gum.
the above. The ease of surfactant cleansing is enhanced if the surface of the tooth has a lower surface energy so that debris and plaque precursors cannot firmly adhere. Besides the obvious hygienic and health benefits related to simple cleanliness provided by surfactants, there is an important cosmetic and sense-of-well-being benefit provided by surfactant cleansing. Research has shown that the primary source of bad breath is the retention and subsequent degradation of dead cellular material sloughed off continuously by the normal, health mouth.
The simple fact is that most of the population brush once a day, some brush morning and evening, but precious few carry toothbrush and dentifrice to use the other three or four times a day for optimal oral hygiene.
Consumer research suggests that the population brushes an average of 1.3 times a day. Thus, the 24 hour period between brushings for a majority of the population provides optimum plaque forming conditions with no interruptions.
Since plaque is regarded by most of the dental profession as a causative agent leading to various dental pathologies as noted above, there is considerable desire by most consumers to remove or prevent the formation of plaque on a daily basis. There are three oral care strategies which address the problem of plaque: abrasion, anti-microbial agents and removal of precursors to plaque.
1. Abrasive removal of the plaque film, once it has firmly adhered to the tooth surface, is the only totally effective cleansing mechanism. Again, professional dental hygiene is the most effective, but recently a number of special abrasive toothpastes have been accepted by dental organizations as partially removing adhered plaque and the tartar which subsequently forms from the plaque;
2. Antimicrobial action could affect plaque formation in two ways, (a) reducing the number of bacteria in the mouth which form the mucopolysaccharides and (b) killing those bacteria trapped in the film to prevent further growth and metabolism. However, the medical and dental community is divided about the advisability of frequent use of antimicrobial agents in the mouth in rinses or prerinses, especially the most effective ones, except under strict supervision of licensed practitioners. There are a number of reasons given, but one concern is that such materials would upset the ecological balance of the mouth. A balanced, "friendly" microbial population is necessary to prevent pathogenic organisms from taking over, and
3. Removal of plaque precursors requires the reduction of food sources and the building blocks required for the bacteria to synthesize the mucopolysaccharides which polymerize into plaque film. Going far back into the chain of events leading to plaque formation and interrupting the chain has much to commend it as a sound oral hygiene strategy. However, for this strategy to be effective, the plaque building blocks must be interrupted periodically. As noted above, hereto, the oral hygiene preparations described above fall short on "frequency-of-use" basis.
For reference, see, L. Menaker, The Biologic Basis of Dental Caries, Chapters 5, 11, 12, 14, 16 and 18, Harper & Row (1980).
Efforts have been made over the years to address the problem of dissolution or demineralization of tooth enamel and the resultant formation of dental caries. As is well known, dental plaque accumulates on the teeth as the result of the growth and metabolism of certain bacteria, such as Streptococcus mutans, which are nourished by cariogenic comestibles, particularly those containing sugars. Such bacteria are involved in the formation of dental plaque which accumulates as a deposit on the surfaces of teeth. The metabolism of bacteria within the plaque results in the generation of high levels of acids which are detrimental to the teeth and contribute to the production of dental caries.
Stannous fluoride, SnF.sub.2, has been used in dentistry since the 1950's as a chemical adjunct to prevent dental caries. Topical applications of SnF.sub.2 consistently have shown dramatic reductions in dental caries activity with minimal side effect. Evidence has also accumulated that SnF.sub.2 has antibacterial properties which may affect its anticaries properties as well as inhibit plaque formation and gingivitis. See Tinanoff, "Review of the Antimicrobial Action of Stannous Fluoride," 1990.
Addy et al., 1988, reported a desensitizing effect for fresh SnF.sub.2 due to a covering or obturation of tubules in hypersensitive dentine. There is also an indication that SnF.sub.2 may be effective in controlling Candida sp. colonization of denture plaque. See Hill et al., U.S. Pat. Nos. 5,057,310; 5,098,711 and 5,165,913.
Prescription (R.sub.x) nonaqueous gels of glycerine and SnF.sub.2, such as Scherer Laboratory's, Gel-Kam are perhaps the most widely used form of R.sub.x SnF.sub.2 available commercially. These gels are generally prescribed for the treatment of caries and hypersensitive teeth as well as gingivitis.
Unfortunately, in spite of its promising results, the effective use of SnF.sub.2 has been drastically limited by its inherent instability in the presence of oxygen, water, abrasives, and the like.
In addition to the inherent instability of SnF.sub.2, most SnF.sub.2 products suffer from poor patient compliance, attributed in part to the nonaqueous carriers required to maintain activity, to the metallic taste of the product, as well as to the methods of application which usually include a brushing step separate and apart from the use of a dentifrice. For example, brush-on SnF.sub.2 gels require the patient to brush at least four times/day, i.e., twice with the gel and twice with a regular dentifrice. Compliance in such a treatment regimen drops to about 30%, an unacceptable level, as documented by Hastrieter's review of Wolf et al.'s 1989 Gel-Kam study.
With the advent of fluoride in water and fluoridated dentifrices, gum disease, gingivitis, hypersensitive teeth, root caries in the elderly and Candida sp. disorders in denture wearers, have replaced caries in children as the dominant oral care concerns of the '90's requiring special treatment. For example, a recent NIH survey established that 90% of adults age 65 or older have some form of gum disease, and over 123 million adults in the U.S. suffer from gum disease. Moreover, one out of six adults suffer from hypersensitivity at one time or another, while ten million adults are chronic sufferers. Additionally, the millions of adults who undergo periodontal treatment, or have their teeth cleaned, can experience hypersensitivity discomfort ranging from an uncomfortable feeling to severe pain. Most denture wearers suffer from "denture breath" attributed in part to Candida sp. colonization of denture plaque and/or plaque-like coatings on dentures.
Recent reviews on dentine hypersensitivity have deduced that the transmission of pain stimuli across dentine is by a hydrodynamic mechanism. This is confirmed by the open tubules (microscopic openings) present in normal teeth). Various stimuli cause fluid movement in these tubules which activate nerve endings in the pulp.
Considerable evidence has accumulated in the past 20 years to show that topical applications of SnF.sub.2 reduce S. mutans levels as well as demonstrate antiplaque properties. These antiplaque and antigingivitis benefits of SnF.sub.2 appear to be related to frequent, i.e., several times/day treatment with SnF.sub.2.
Root caries is attributed to the recession of gums and is a common condition in the elderly. Candida sp. yeast disorders are estimated to occur in approximately 90% of denture wearers. These disorders lead to, or are associated with, stomatitis and thrush (candidiasis).
There is therefore a definite need in the art for oral hygiene preparations containing microbially active SnF.sub.2 that retain the desired antibacterial activity over the use life of the preparations. There is also a need in the art for oral hygiene preparations containing microbially active SnF.sub.2 that are pleasant to use, encourage compliance and support frequent usage throughout the day. There is a further need in the art for new methods of treating caries, coronal caries, gingivitis, plaque buildup, hypersensitivity and Candida sp. infections of denture plaque with microbially active SnF.sub.2 products in various forms.
There is a further need in the art for delivery vehicles for microbially active SnF.sub.2 which achieve rapid transport of SnF.sub.2 into fissures, crevices in dentures and other prosthesis where the microbial activity of SnF.sub.2 can be employed to fight plaque and disrupt the colonization of denture plaque by yeast type organisms while protecting the SnF.sub.2 from degradation of its microbial activity.
In view of the foregoing it is an object of this invention to provide an oral hygiene preparation that disrupts plaque formation with or without providing various therapeutic substances to the oral cavity such as SnF.sub.2 for treating caries, gingivitis, hypersensitivity and Candida sp. infections.
It is also an object of this invention to provide an oral hygiene preparation containing various therapeutic substances including microbially active SnF.sub.2 that are pleasant to use, encourages compliance and repetitive usage.
It is a further object of this invention to provide an effective method for treating caries, gingivitis, hypersensitivity, plaque buildup and Candida sp. infections.
It is yet another object of this invention to provide a method of manufacturing oral hygiene preparations for fighting plaque as well as preparations containing a microbially active form of SnF.sub.2.
Chewing gum has over the years been advocated as a possible excellent adjunct for cleaning the teeth because people find the chewing of gum very pleasurable and chew gum more frequently for much longer periods of time than they brush their teeth. Chewing gum is especially advantageous for use in circumstances where tooth brushing is not possible or convenient, such as after lunch, while traveling, or while working.
Chewing gum stimulates saliva because of the chewing action, flavors and sweetness. In the first few minutes of chewing, studies have shown a ten-fold increased in salivary flow. After the flavor and sweeteners are extracted, there is still a three-fold increase in saliva flow. This saliva stimulation after eating has a number of benefits. For example, stimulating saliva after eating helps:
Most eating occasions lead to prolonged acid production. Dentists advise snacking in moderation, brushing teeth twice daily with a fluoride toothpaste, and cleaning teeth soon after eating. However, since tooth brushing with toothpaste after eating is often impractical and inconvenient, the use of a salivary stimulant can reduce acid production and facilitate a returning to a near neutral pH conductive to remineralization. Two recent papers by Dr. S. L. Creanor, et al., in Glasgow and Drs. R. H. Manning and W. M. Edgar in Liverpool on remineralization illustrates the importance of stimulating saliva after eating in a fluoride environment, e.g., Caries Res. (26.3.92 No. 22, Page 215 and J. Clin. Dent., Vol. III No. 3, respectively.
As is well known, salivation is an important physiological function which has several benefits in addition to those relating to digestion.
One of those benefits is the washing of tooth enamel surfaces and their surrounding soft tissues or game. This washing provides a preventive effect against disease in direct relation to the rate of salivary flow from the four major salivary glands which empty into the human mouth under various stimulations.
Chewing gum not only provides the flavor and chewing factors for saliva stimulation but also achieves mechanical dental cleansing, making it an ideal and natural mechanism for promoting dental health.
The use of chewing gums to deliver various substances into the oral cavity is extensively described by the prior art. Generally, these references teach incorporating various substances into the gum mix during the processing of the gum. The substances incorporated in the gum base are then released from the gum during masticating. For example;
The "Effect of Chewing Gums Containing Xylitol, Sorbitol or a Mixture of Xylitol and Sorbitol on Plaque Formation, Ph Changes and Acid Production in Human Dental Plaque": is published in Carles Res., 17: 369-378 (1983).
Historically, researchers in gum have focused on incorporating various substances from flavors to plaque fighting substances into the gum base, or gum base adjuncts for controlled released during chewing. For example:
The general disclosure of nonionic surfactants for use in oral products is also well discussed in the prior art, particularly with reference to dentifrices and rinses. For example:
Hill et al., U.S. Pat. Nos. 4,950,479 and 5,057,309 disclose the claimed emulsions of the present invention in "liquid center chewing gums". However, there is no teaching or suggestion that the Hill et al. emulsions can be coated onto chewing gum and subsequently released into the oral cavity at a predetermined plaque disrupting level and rate.
One of the leading researchers in gum technology, the Wm. Wrigley Jr. Company, has contributed various innovations to chewing gum technology, including:
The release of active ingredients from the gum base is a major problem and one which has confronted the industry for a long time despite the fact that slab chewing gums on a weight basis are more than 75% water soluble materials such as sugars, sugar substitutes, corn syrup, and the like.
It therefore has been the usual practice in the industry when manufacturing chewing gums having active ingredients to deposit the active ingredient upon the exterior of a gum nugget or center, usually with an underlying thin layer of hard sugar. The outer layer of hard sugar is generally produced by tumbling the units in coating pans into which saturated solutions of sugar are poured and the water driven out by aeration, the finished piece being commonly called "candy coated gum". The use of candy coated gum allows for the dissolution of the active ingredient in the mouth before it is chewed into the gum base. See U.S. Pat. Nos. 3,075,884 and 3,011,949. This method of production is costly and eliminates desired slab forms of gum containing such an active ingredient. See also U.S. Pat. Nos. 1,629,461, 1,771,982 and 2,198,165.